U.S. patent application number 15/548501 was filed with the patent office on 2018-08-23 for powder press having a cone-shaped substructure.
The applicant listed for this patent is GKN Sinter Metals Engineering GmbH. Invention is credited to Eberhard Ernst, Rainer Schmitt.
Application Number | 20180236547 15/548501 |
Document ID | / |
Family ID | 55273268 |
Filed Date | 2018-08-23 |
United States Patent
Application |
20180236547 |
Kind Code |
A1 |
Schmitt; Rainer ; et
al. |
August 23, 2018 |
Powder Press Having a Cone-Shaped Substructure
Abstract
The invention relates to a powder press, comprising a tool
structure, which has a conical substructure having lower rams
nested in each other, wherein each lower ram has a longitudinal
extent, in particular a cylindrical longitudinal extent, which is
guided in a die, wherein, in the case of at least two longitudinal
extents of the lower rams, each longitudinal extent is adjoined by
a conical enlargement, wherein the conical enlargements can be
guided in each other, wherein the region of the conical enlargement
has an inner wall and an outer wall, which expand conically and
which are preferably longer than the longitudinal extent. The
invention further relates to a method for operating a powder press
and to a computer program product having computer program code
means that can be executed on a computer system in order to perform
the method.
Inventors: |
Schmitt; Rainer; (Wachtberg,
DE) ; Ernst; Eberhard; (Eichenzell, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GKN Sinter Metals Engineering GmbH |
Radevormwald |
|
DE |
|
|
Family ID: |
55273268 |
Appl. No.: |
15/548501 |
Filed: |
February 1, 2016 |
PCT Filed: |
February 1, 2016 |
PCT NO: |
PCT/EP2016/052013 |
371 Date: |
August 3, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B30B 11/02 20130101;
B30B 15/065 20130101; B22F 3/03 20130101; B30B 15/026 20130101;
B30B 15/26 20130101; B22F 3/003 20130101; B22F 2003/033
20130101 |
International
Class: |
B22F 3/03 20060101
B22F003/03; B30B 11/02 20060101 B30B011/02; B30B 15/06 20060101
B30B015/06; B30B 15/26 20060101 B30B015/26; B22F 3/00 20060101
B22F003/00; B30B 15/02 20060101 B30B015/02 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 4, 2015 |
DE |
10 2015 201 966.7 |
Claims
1. A powder press comprising a tool structure which has a conical
substructure and/or superstructure with punches, upper and/or lower
punches, nested in one another, wherein each punch has a
longitudinal extent, which is a cylindrical longitudinal extent,
which is guided in a die, wherein at least two longitudinal extents
of the punches are adjoined in each case by a region with a conical
enlargement, wherein the conical enlargements are able to be guided
one in another, wherein the region of the conical enlargement has a
conically expanding inner and outer wall, which are longer than the
longitudinal extent.
2. The powder press as claimed in claim 1, wherein, apart from an
innermost punch, all punches have an enlarging region which expands
in a conical, in particular cone-shaped or bell-shaped manner.
3. The powder press as claimed in claim 1, wherein a conical
extension is located on at least two respective punches arranged as
a structure, said conical extension continuing a corresponding
conical inner and outer wall of the conical enlargement.
4. The powder press as claimed in claim 3, wherein the combination
of the region with a conical enlargement and a conical extension is
longer than the longitudinal extent.
5. The powder press as claimed in claim 3, wherein a cone angle at
which the conical enlargement and the conical extension extend away
from a press axis is at least approximately the same.
6. The powder press as claimed in claim 1, wherein, in a common end
position, feet of the respective punches end at different heights
than one another.
7. The powder press as claimed in claim 1, wherein, compared to one
another, the punches that slide in one another have approximately
the same elasticity in the region of conical enlargement.
8. The powder press as claimed in claim 1, wherein compared to one
another, the punches, with a conical structure that slide in one
another have approximately the same elasticity.
9. The powder press as claimed in claim 1, wherein feet of the
punches end at the same height along a plane in a common end
position.
10. The powder press as claimed in claim 1, wherein an outermost
punch deflects approximately as much as an associated inner
punch.
11. The powder press as claimed in claim 1, wherein an outermost
punch together with a structure deflects approximately as much as
an associated inner punch with a structure.
12. The powder press as claimed in claim 1, wherein a respective
cone angle of the punches of a superstructure and/or substructure
increases from the inside out, while the respective longitudinal
extent of the punches decreases from the inside out.
13. The powder press as claimed in claim 1, wherein a respective
cone angle of the punches of a superstructure and/or substructure
remains at least approximately the same from the inside out.
14. The powder press as claimed in claim 1, wherein a punch holder
directly adjoins the conical enlargement.
15. The powder press as claimed in claim 1, wherein the conical
enlargement of the respective upper and/or lower punch increases to
such an extent that an associated punch holder terminates flush
with the upper or lower punch laterally on the outside.
16. The powder press as claimed in claim 1, wherein the conical
enlargement of the respective upper and/or lower punch transitions
into a cylindrical portion, wherein the cylindrical portion has a
fastening structure for a punch holder.
17. The powder press as claimed in claim 16, wherein a punch holder
is connected directly to a lower punch by a bayonet fastener.
18. The powder press as claimed in claim 1, wherein a connection
between a punch holder and punch takes place without a pressure
plate and clamping plate.
19. The powder press as claimed in claim 1, wherein at least one
upper punch and/or one lower punch are produced in one piece.
20. The powder press as claimed in claim 1, wherein at least one
upper punch and/or one lower punch are produced in a multipart
manner.
21. The powder press as claimed in claim 1, wherein the punches
units that slide in one another are provided with in each case a
different ratio of length of the a head piece to length of the
conical enlargement.
22. A method for operating a powder press in which punches, upper
and/or lower punches, according to claim 1, that slide in one
another are moved, wherein monitoring in the form of control or
regulation is employed, this effecting equalization between
different springing behavior of the punches that slide in one
another when the pressure on a pressed workpiece is relieved.
23. The method as claimed in claim 22, wherein electronic
compensation of a difference in elastic deflection takes place.
24. The method as claimed in claim 22, wherein equalization via
position control takes place while the lower and/or upper punches
are being moved.
25. The method as claimed in claim 22, wherein a compact made of
metal powder is created.
26. A method of setting up of a powder press with a set of punches
according to claim 1 that slide in one another, wherein said
punches are first of all installed together and are then jointly
set up.
27. A compact produced with a powder press as claimed in claim 1,
wherein a density along a cross section of the compact is
constant.
28. Lower punches that slide in one another of a powder press,
having at least a plurality of punches, as claimed in claim 1.
29. A punch of a powder press as claimed in claim 1.
30. A conically shaped structure of a punch of a powder press as
claimed claim 1.
31. A computer program product with computer program code which are
able to be run on a computer system in order to carry out a method
as claimed in claim 22.
Description
[0001] The present invention relates to a powder press having a
conical lower punch, in particular substructure, and to a
production method and a compact produced with the proposed powder
press. The powder press is used to produce in particular bodies
that are subsequently to be sintered. In particular, it is possible
for metal powders but also ceramic powders to be processed. The
compact is preferably a green compact which is subsequently
sintered.
[0002] A press structure is a decisive factor for determining what
kinds of parts can be pressed for how long in what way. The
applicant's DE 10 2014 003 726 discloses a press for producing
dimensionally accurate green compacts, in which the tool structures
used are optimally designed for equalizing elasticity between
individual tool levels. To this end, a certain amount of technical
effort is required in designing and also producing the tools.
[0003] The object of the present invention is to create a
simplified press structure which can be produced by conventional
methods and shortens the time required for a tool change in
addition to time for setup.
[0004] This object is achieved by a powder press having the
features of claim 1, by a method having the features of claim 22, a
method for setting up having the features of claim 26, by a compact
having the features of claim 27, lower punches that slide in one
another having the features of claim 28, a lower punch having the
features of claim 29, a structure having the features of claim 30
and a computer program product having the features of claim 31.
Advantageous developments and configurations can be gathered from
the respective dependent claims, wherein one or more features from
the description and also from the figures can be combined to form
further configurations. The wording of the independent claims
should furthermore be understood as being a first attempt to
reproduce the subject matter of the invention. Therefore, one or
more features of the independent claims can be supplemented by one
or more features from the disclosure, exchanged therefor or even
deleted in order to comprehend the subject matter of the invention
better.
[0005] A powder press having a tool structure is proposed, wherein
the tool structure has a conical substructure with lower punches
nested in one another, wherein each lower punch has a longitudinal
extent, in particular a cylindrical longitudinal extent, which is
guided in a die, wherein at least two longitudinal extents of the
lower punches are adjoined in each case by a region with a conical
enlargement, wherein the conical enlargements are able to be guided
one in another, wherein the region of the conical enlargement has a
conically expanding inner and outer wall, which are preferably
longer than the longitudinal extent. Preferably, the lower punch
forms a length here which is otherwise allowed only with an
attached structure. Preferably, the lower punch has at its end an
expansion of such a size that, for example, a punch holder is able
to be connected directly to this end of the lower punch.
[0006] The longitudinal extent extends parallel to an axis of
movement of the powder press. Preferably, the longitudinal extent
is arranged concentrically about the axis of movement of the powder
press. The longitudinal extent is realized, for example, by a head
piece in a punch.
[0007] The lower punch preferably forms the substructure. This
means that the lower punch extends axially and radially in a
cone-shaped manner as a hollow cone such that a foot of the lower
punch rests for example directly on a pressure plate, or is in
direct contact with a drive. In this way, it is possible, for
example, for the use of an adapter plate per lower punch to be
dispensed with. It is preferred for the pressure plate to be
integrated in the punch. To this end, it is possible for example to
provide for a punch foot to have a width and a thickness which
allow direct connection of a drive. In a further configuration, a
connection for the pressure plate is provided at the foot of the
punch, preferably a connection which functions via a relative
rotation between the pressure plate and punch.
[0008] Otherwise, the explanations given above and below apply not
only to the lower punch. Rather, it is possible for one or more
upper punches to be designed or configured in the same way.
According to a further concept of the invention, it is possible in
particular for such upper punches, like the proposed lower punches,
to be pursued as an independent concept and in combination with the
lower punches. The same goes for conical punches with conical
structures. In the following text, embodiments, features and
further advantages will be explained in more detail by way of an
application to lower punches, but without limiting this to lower
punches. Rather, corresponding considerations also apply to upper
punches and combinations of such upper and lower punches. In the
rest of the text, only the term punch will also be used. This is
then understood to mean upper punches and lower punches. A
superstructure in turn relates to the structural design down to a
pressure plate of the associated upper punch. A substructure
relates to the structural design down to a pressure plate of the
associated lower punch. Corresponding considerations as for the
upper and lower punches are also possible for a punch having a
conically expanding structure, which will be discussed in more
detail in the following text.
[0009] In one development, for example, apart from an innermost
lower punch, all lower punches have an enlarging region which
expands in a conical, in particular cone-shaped or bell-shaped
manner.
[0010] In a further configuration, a conical extension is located
on at least two, preferably all respective lower punches, possibly
without the innermost lower punch, arranged as a structure, said
conical extension continuing a corresponding conical inner and
outer wall of the conical enlargement.
[0011] Preferably, the combination of the region with a conical
enlargement and a conical extension can be longer than the
longitudinal extent. In particular, a substructure is formed in
this way. The substructure is in the form of a hollow cone.
[0012] Provision can furthermore be made for the cone angles of
lower punches that are slidable in one another, or lower punches
with extensions, at which the conical enlargement and the conical
extension extend away from a press axis, to be at least
approximately the same. It is thus preferred for a respective cone
angle of the lower punches to remain at least approximately the
same from the inside out. However, it is also possible for the cone
angles to deviate from one another, wherein the cone angles
preferably spread out further from the inside out.
[0013] A constant cone angle along the radial extent has the
advantage that an effect of bending or a risk of kinking when the
pressing forces pass through is very greatly reduced and instead
stress distribution becomes very even across the expansion.
Preferably, bending stresses in a longitudinal direction can be
very greatly reduced by means of the proposed solution.
[0014] Furthermore, provision is made for example for the lower
punches pushed into one another not to be in contact in the region
of their expansion, i.e. with the respective inner wall of the one
punch and the opposite outer wall of the opposite punch, preferably
not to be in contact at least over most of the expanding extent. A
corresponding provision is likewise made for example for an
expanding punch having a conically expanding structure and an
adjacent punch with an adjacent expanding structure. Provision is
made for example for contact between the punches to occur only
along a part of a longitudinal extent of the punches, preferably
only along an extent of 10 to 30 mm, more preferably only in the
region of a die of the powder press. According to one development,
provision is made for example for a longitudinal extent of a punch
to have what is known as a clearance. A clearance means that the
previous dimension of the diameter of the longitudinal extent of a
punch is changed to such an extent that no contact with an adjacent
punch occurs, but there is otherwise contact in the region of the
die. The contacting region in the die serves as a guide, in
particular as an upper guide for lower punches and as a lower guide
for corresponding upper punches.
[0015] In another configuration of the powder press, in a common
end position, feet of the respective lower punches end at different
heights than one another.
[0016] Preferably, compared to one another, the lower punches that
slide in one another have approximately the same elasticity in the
conically expanding region. For example, compared to one another,
the lower punches with a conical structure that slide in one
another can have approximately the same elasticity.
[0017] It is also possible for feet of the lower punches to end at
the same height along a plane in a common end position. In
particular, as a result of the proposed solution, an outermost
lower punch, or an outermost lower punch with a conically expanding
structure, deflects approximately as much as an inner lower punch,
or a lower punch with a conically expanding structure. To this end,
it is possible for example for the modulus of elasticity and the
respective structure to be configured in a corresponding manner in
order to set a desired stiffness. Preferably, a stiffness can be
increased by design measures. In this way, it is possible to get a
grip on the high friction forces that occur for example at the
outermost punch and the resulting changes in length on account of a
material heating up with an associated change in friction during
operation. In particular, structural compensation and, moreover, a
convergence of the deflection is created, even in the case of
different lengths, as for example in the case of the inner punch,
since the great length thereof can result in greater changes in
length and greater deflection than in the case of shorter punches.
Consideration should also be given here to the fact that, for
example, it is possible to combine cone-shaped, long lower punches
without structures additionally expanding in a cone-shaped manner
and lower punches having structures expanding in a cone-shaped
manner. The latter preferably do not exhibit any contact with the
adjacent punch in the region of their expansion, but at least do
not exhibit any contact with the adjacent punch along most of their
extent.
[0018] In a further configuration, an outermost lower punch
together with a structure deflects at least approximately as much
as an inner lower punch with a structure. The advantage of these
configurations arises during pressing and in particular when the
pressed material is relieved of load, since, as a result, easier
load relief across all punches is possible, without the green
compact breaking.
[0019] According to a further concept, which can be independent of
and also dependent on the above text and the following text, a
design method for determining a structural solution of the
cone-shaped lower punches that are movable in one another, or
cone-shaped lower punches with cone-shaped structures, is proposed.
In this case, a first evaluation of each lower punch or attached
structure is carried out and a check is made as to whether an abort
criterion, for example the respective elasticity, has converged
with a definable abort criterion, and otherwise at least one
parameter is changed until at least this one abort criterion has
been met. In this way, depending on specification, the
corresponding lower punches that are movable in one another, or
lower punches with structure, can be evaluated and designed for
example for a converged, in each case uniform elasticity
overall.
[0020] Preferably, provision is furthermore made for a respective
cone angle of the lower punches to increase from the inside out,
while the respective longitudinal extent of the lower punches, or
the longitudinal extent of the lower punches with the respective
structures, decreases from the inside out.
[0021] Furthermore, provision is preferably made for a punch holder
to directly adjoin the conical enlargement. The conical enlargement
of the respective lower punch preferably increases to such an
extent that an associated punch holder terminates flush with the
lower punch laterally on the outside. In a development,
alternatively or in addition, there is flushness on the inside. In
this case, provision can be made for the conical enlargement of the
lower punch to transition into a cylindrical portion, wherein the
cylindrical portion has fastening means for a punch holder,
preferably releasable fastening means. Preference is given for
example to rotary closures, which make in particular a
screw-connection superfluous. It is furthermore preferred for a
punch holder to be connected directly to a lower punch by means of
a bayonet fastener. This makes it possible, in particular, for a
connection between the punch holder and lower punch to take place
without a pressure plate and clamping plate.
[0022] In the case of a bayonet fastener, it has been found to be
advantageous for a fit of the bayonet fastener to have more play
radially than axially. The radial play can in this case be greater
by a factor of 10 to 50.
[0023] In a further configuration, the punches, with or without a
structure, adopt such an expanding width that a drive, in
particular one or more hydraulic cylinders, can be arranged thereon
directly and/or via an adapter plate. Preferably, a foot of the
punch or of the structure is so stable that direct contact is also
allowed. To this end, it is possible, for example, for that end of
the structure or of the punch that is located opposite the
longitudinal extent to have a collar.
[0024] With regard to the structure of the punch, provision can be
made for at least one upper punch and/or one lower punch to be
produced in one piece. It is also possible for at least one upper
punch and/or one lower punch to be produced in a multipart
manner.
[0025] Furthermore, provision is made for the punch units that
slide in one another to be provided with in each case a different
ratio of length of the head piece to length of the enlarging
region.
[0026] According to a further concept of the invention, which can
be pursued independently of and also in dependence on the above
concept, a method for operating a powder press is proposed, in
which punch units that slide in one another, as described above
and/or below, are moved, wherein monitoring in the form of control
or regulation is employed, this effecting equalization between
different springing behavior of the punch units that slide in one
another when the pressure on a pressed workpiece is relieved.
Preferably, the equalization is carried out by electronic
compensation. In particular, for this purpose, equalization can
take place via position control while the lower punches are being
moved. Preferably, the method is used in order to create a compact
comprising metal powder. Thus, it is possible, for example, to
provide here for one punch to spring, while another punch moves,
when the pressure on the pressed green compact is relieved. In a
further configuration, during setup, equalization on account of
different springing behavior of the respective punches or punches
with structures does not happen. Rather, equalization is carried
out only by position detection and position control, without prior
setting with regard to the elasticity differences.
[0027] According to a further concept of the invention, which can
be pursued independently of and also in dependence on the above
concept, installation of a set of punch units that slide in one
another in a powder press is proposed, as described in more detail
above and below, wherein these punch units are first of all
inserted together and then jointly fastened, i.e. mounted. As a
result, individual insertion and individual orientation, as before,
is dispensed with. It is also subsequently possible for joint setup
to take place. During setup, the filling position, the transfer
position, the compression, the relief of pressure and the demolding
are preferably checked and finely adjusted with all punch units
together. A punch unit otherwise comprises the proposed conical
punch and also the conical punch with a conical structure.
[0028] An advantage of the proposed powder press is that a compact
is able to be produced which has a constant density along a cross
section of the compact. It is also possible to fulfill complex
shapes, since breakage of the green compact is avoided on account
of approximately identical elasticities when the punches are moved
away. Preferably, elasticity is designed such that, under operating
conditions, respective deflection or rebounding of 5/10 mm or less
takes place over all punches.
[0029] Furthermore, it is proposed for lower punches that slide in
one another of a powder press to be provided, which have at least a
plurality of lower punches as described above and below.
[0030] According to one configuration, the present invention
likewise allows a simplified tool structure while at the same time
dispensing with conventional ancillary equipment, in particular
pressure plates, with for example the aim of: [0031] force flow
optimization implementable by a geometrically simple, funnel-shaped
tool design, particularly in the case of rotationally symmetrical
tools; [0032] reduced effort in construction by dispensing with
design optimization; [0033] dispensing with additive manufacturing
methods, since the simple tool elements can generally be produced
on standard machine tools by machining methods; [0034] shortening
the inner tool elements, also with acceptance of the lengthening of
the outer tool elements; [0035] dispensing with complete elasticity
equalization: equalization is generally still carried out by
position control by the machine.
[0036] The tool structures can consist, both in one piece and also
in a multipart manner by connecting technology, of optionally a
head piece, connecting element and foot piece.
[0037] Furthermore, in the scope of the disclosure, reference is
also made to the applicant's DE 10 2015 201 784.2 and to the
applicant's DE 10 2015 201 785.0 with regard to a possible
configuration of lower punches that are displaceable in one
another. With regard to a possible production method, in the scope
of the disclosure, reference is made to the applicant's DE 10 2015
201 775.3.
[0038] In particular, as far as uniform pressure application and
especially relief of pressure across a width of the compact is
concerned, it is advantageous for the lower punches to be
constructed in a rotationally symmetrical manner. A further
configuration provides punches that are not rotationally
symmetrical, in particular asymmetrical, with their punch feet on
rotationally symmetrical structures. In this case, the punch feet
are preferably likewise rotationally symmetrical. It is also
possible for example for asymmetrical foot stiffness to be
provided, which serves to provide equalization between a load side
and a less loaded side of the asymmetrical punch.
[0039] According to a further concept of the invention, which can
be pursued independently of and also in dependence on one of the
concepts above and/or below, a lower punch and/or upper punch of a
powder press, as described above and/or below, is proposed.
[0040] According to a further concept of the invention, which can
be pursued independently of and also in dependence on one of the
concepts above and/or below, a structure for connection to a lower
punch and/or upper punch of a powder press, as described above
and/or below, is proposed.
[0041] According to a further concept of the invention, which can
be pursued independently of and also in dependence on one of the
concepts above and below, a computer program product with computer
program code means which are able to be run on a computer system in
order to carry out a method, as described above and/or below, is
proposed.
[0042] Further advantageous features and configurations can be
gathered from the following figures. One or more features from one
or more figures and also from the description above and below can,
in this case, be combined to form further configurations. In
particular, the figures serve to explain the invention and are not
intended to limit the latter. Observations and statements which
relate to lower punches and lower punches with a conical structure
are not limited to lower punches but serve for clarification by way
of example. The respective features and configurations are likewise
able to be used in proposed upper punches or proposed upper punches
with an additional conical structure of a powder press. In the
figures:
[0043] FIG. 1: shows a detail of a powder press as is known from
the prior art,
[0044] FIG. 2: shows an exemplary, schematic adapter structure
without a tool and substructure but with adapter plates and column
structure from the prior art,
[0045] FIG. 3: shows an exemplary, schematic view of lower punches
that are movable in one another, as are known from the prior
art,
[0046] FIG. 4: shows an exemplary, schematic configuration
according to the invention of lower punches and attached structures
compared to the illustration in FIG. 3,
[0047] FIG. 5: shows an exemplary schematic design solution with
expanding lower punches according to the proposed invention,
[0048] FIG. 6: shows a comparison of the different springing
behavior or elasticity the use of the different systems according
to FIG. 3 and according to FIG. 4, and
[0049] FIG. 7: shows a schematic view of a proposed powder
press.
[0050] FIG. 8: shows an enlarged view of the powder press from FIG.
7 in order to illustrate stops.
[0051] FIG. 1 shows a detail of a powder press 1 as is known from
the prior art. This detail shows a part of a tool 2, wherein,
however, neither a die nor an upper punch or other components of
the powder press 1 are illustrated. What is shown is an adapter
plate structure 3 with a lower punch 4. As ancillary equipment, use
is made of a screwed-on lock bush 5, a pressure plate 6 and a
support ring 7. By means of the lock bush 5, a punch foot 8 is
fastened to the pressure plate. The structure of the punches shows,
for the one part, the necessary size that has to be provided for
such a powder press. For the other part, the setup requires a
certain effort, since, for this purpose, the lock bushes or
clamping plates and pressure plates also have to be installed, this
taking place individually.
[0052] FIG. 2 shows an adapter plate structure from the prior art
in a simplified, clear illustration. For the upper and also the
lower punches, which are not shown in more detail here, an adapter
plate has to be installed in each case per punch. Little by little,
one adapter plate after another can be attached upwardly and also
downwardly, for which purpose the respective structure has to be
moved in the press. This operation is very time-consuming and
requires a large number of individual parts.
[0053] FIG. 3 likewise shows a simplified sectional view, for
better understanding, of a structure, known from the prior art,
with a lower punch 9 and attached structures 10. These extend, as
already illustrated in FIG. 1, substantially along a movement axis
of the press. In particular, the respective inner and adjacent
outer wall of adjacent punches slide on one another, since, in such
a structure, the punches are guided thereby.
[0054] FIG. 4 shows a structure according to the invention with
lower punches 11 which have a conical expansion, to which
respective cone-shaped structures 12 are attached, to which a punch
holder for example is then directly attachable. The structures 12
are connected here to the lower punches 11 by feet 13 that are
illustrated only schematically. It is preferred, as illustrated,
for an angle of the conical expansion of the respective lower punch
11 to be adopted and continued by the cone-shaped structure 12. An
exemplary configuration is a substantially conical-rectilinear
embodiment of the expansion. A bell-like design of the expansion is
likewise possible. As illustrated, contact occurs only in the
region of the lower punches, and in that case only in the region of
the longitudinal extent 11.1 thereof. Otherwise, the walls are
spaced apart from one another.
[0055] FIG. 5 shows an exemplary, schematic design solution, in
which the illustrated lower punches 13 move in one another and a
conical expansion results overall. Attached to the punch feet are
conical structures 14, the conical profile of which continues as
far as the illustrated adapter plates 15.
[0056] FIG. 6 shows a comparison of the respective elasticity
firstly with the type 1 system from FIG. 3 and secondly with the
type 2 system from FIG. 4. As illustrated, it is possible to bring
the corresponding properties of the respective lower punches or
lower punches with a structure very close to one another, as
proposed. This can result, in particular, for example, in the press
control not needing any elasticity equalization between the punches
during movement, in particular during relief of pressure.
[0057] FIG. 7 shows a schematic, simplified view of a powder press
17 according to the invention. For better understanding, the
individual components of the powder press 17 are provided with
reference signs in the figure and explained in the following text.
The illustrated section is not planar, but partially rotated for
the sake of clarity. As a result, those components are also visible
which, arranged around a periphery of the powder press 17, would
not otherwise be visible. A crosshead 18 of the powder press 17 is
connected to a hydraulic main cylinder 19 for a pressing force.
However, it is also possible for some other drive to be provided,
for example a worm drive. Furthermore, the crosshead 18 is firmly
connected to two illustrated guide columns 20. An upper top plate
21 is movable, wherein, for example, at least two diagonally
opposite hydraulic cylinders 22 per level are used. Each level
preferably has hollow cones 23 as a conical expansion of a
structure or of a punch with in each case at least two stiff arms
24 with guide bearings 27, each with respect to two diagonally
opposite columns. A die plate 25 with the die 26 is held in a
movable manner. As a result, a take-off method can be implemented.
A drive for this purpose can also be provided in a base plate. The
machine base plate 28 of the powder press 17, also known as
foundation plate, has at least two diagonally opposite cylinders,
preferably hydraulic cylinders 29, per level, which are connected
to a hollow cone 30, specifically one each per tool-punch level.
The machine base plate 28 bears the hydraulic cylinders 29 and is
firmly connected to the columns 31. The hydraulic cylinders 29 can
be replaced for example completely or in part by some other drive,
for example by a respective electric spindle drive. Also
illustrated are the lower punches 32 with attached structures in
the form of the hollow cones 30. In the region of the substructure,
too, the lower punches or the hollow cones 30 are supported via
stiff arms 33. Otherwise, it should be noted that, for the sake of
clarity, only the sections through the shaping tools and the
conical structure parts are illustrated in a hatched manner.
[0058] According to a further concept, which can be independent of
or dependent on the above and the following, a guide of the punch
units is proposed, which has a first contacting region in the die
as guide, in particular as an upper guide for lower punches and as
a lower guide for corresponding upper punches. A second guide takes
place as an external guide of the hollow cones, as explained and
illustrated above. In this way, defined movability along a powder
press axis can be created.
[0059] FIG. 8 shows a detail of the illustration in FIG. 7.
However, for better clarity, the hydraulic cylinders have been
omitted and various stops 34 illustrated instead. Said stops can be
used according to one configuration. A stop can be arranged in a
stationary and also in an adjustable manner.
* * * * *